The present invention relates to an improved bidirectional mapping catheter that is particularly useful for mapping electrical activity in a tubular region of or near the heart.
Atrial fibrillation is a common sustained cardiac arrhythmia and a major cause of stroke. This condition is perpetuated by reentrant wavelets propagating in an abnormal atrial-tissue substrate. Various approaches have been developed to interrupt wavelets, including surgical or catheter-mediated atriotomy. Prior to treating the condition, one has to first determine the location of the wavelets. Various techniques have been proposed for making such a determination. None of the proposed techniques, however, provide for measurement of the activity within a pulmonary vein, coronary sinus or other tubular structure about the inner circumference of the structure.
The present invention is directed to a bidirectional catheter having a mapping assembly and a method for measuring electrical activity within a tubular region of or near the heart, e.g., a pulmonary vein, the coronary sinus, the superior vena cava, or the pulmonary outflow tract. The mapping assembly, which has a generally circular region with a series of spaced-apart electrodes mounted thereon, is positioned within the tubular region so that the electrodes are in contact with an inner generally circumferential surface inside the tubular structure.
In one embodiment, the invention is directed to a bidirectional mapping catheter. The catheter comprises an elongated flexible tubular catheter body having an axis and proximal and distal ends. A mapping assembly, which is mounted at the distal end of the tubular body, has a preformed generally circular main region having an outer surface. The generally circular main region is generally transverse to the axis of the catheter body, has proximal and distal ends and carries a plurality of spaced apart electrodes. An electrode lead wire is associated with each electrode. Each electrode lead wire has proximal and distal ends and extends through the catheter body and into the mapping assembly. The distal end of each electrode lead wire is electrically connected to its associated electrode. First and second puller wires are provided. Each puller wire has proximal and distal ends and extends through the tubular catheter body. The distal end of each puller wire is anchored at or near the distal end of the catheter body. A handle is connected to the proximal ends of the catheter body and puller wires for moving the puller wires longitudinally relative to the catheter body. Longitudinal movement of a puller wire relative to the catheter body results in deflection of the distal end of the catheter body.
In another embodiment, the invention is directed to a method for mapping electrical activity within a tubular region of or near the heart having a inner circumference. The method comprising inserting into the heart the distal end of a catheter as generally described above. The outer circumference of the generally circular main region is contacted with the inner circumference of the tubular region. The electrical activity within the tubular region is mapped with the at least one electrode along the generally circular main region.